ABSTRACT
This chapter suggest that the molecular signals regulating Brown Adipose Tissue (BAT) growth may be different from those which increase the production of Ucp mRNA and the concentration of uncoupling protein in BAT. Nonshivering thermogenesis (NST) in mammals is an important source of heat production in neonates and during cold exposure and hibernation. Associations between obesity, energy metabolism and NST have been well documented, but understanding the control of BAT growth in adult mammals has proven difficult. Postnatal development of BAT in many mammals is characterized by tissue involution and/or conversion to white adipose tissue. Adult arctic ground squirrels spontaneously increase food intake from about 35 gm lab chow per day during June and July to approximately 60 gm per day in mid August to late September before entering hibernation. For the arctic ground squirrel, the insulation of the burrow should significantly buffer drastic reductions in ambient temperature during prehibernation, thereby eliminating the need for NST.
